Governor for electric motors



(No ModeL) G. H. WHITTINGHAM.

GOVERNOR FOR ELECTRIC MOTORS.

No. 408,333. Patented Aug. 6, 1889.

Mentor/.-

z'zigkam' UNITED STATES PATENT OFFICE.

GEORGE H. VVHITTINGHAM, OF BALTIMORE, MARYLAND.

GOVERNOR FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 408,333, dated August6, 1889.

Application filed Dotoher 9, 1888. Serial No. 287,657! (No model.)

To aZZ whom it may concern:

Be it known that l, GEORGE H. \VHITTING- HAM, a citizen of the UnitedStates, residing at Baltimore, State of Maryland, have invented certainnew and useful Improvements in Electric-Motor Governors, of which thefollowing is a specification, reference being had therein to theaccompanying drawings.

This invention has relation to an electric-' motor governor, the objectbeing to provide an electrical device or devices to be used inconnection with a centrifugal or other me chanical governor in such amanner that as the variations in the speed of the motor shall affect themechanical governor it 'in turn shall serve to vary the strength of thefield of the motor. By such a construction and arrangement of themechanisms employed a motor when relieved of a portion of its load or ofthe work it is performing will increase its speed of rotation, whichincrease, being communicated to the mechanical governor, will serve toreduce the magnetic strength of the field of the motor. 011 the otherhand, should load or work of the motor be increased, the motor willnaturally rotate with a reduced speed, which, being communicated to thegovernor, will cause it to increase the strength of the field.

One of the principal objects of the invention is to provide electricaldevices co-operating with the mechanical governor, which will not beliable to become fused at the contactpoints, and which shall be subjectto the operation of the mechanical governor in such a manner as to shuntthe supplying-current in accordance with the variations of the load ofthe motor.

Other objects and advantages of the invention will hereinafter appear,and the novel features thereof will be particularly pointed out in theclaims.

Referring to the drawings, Figure 1 is a side elevation of anelectric-motor governor constructed in accordance with my invention.Fig. 2 is a plan. Fig. 3 is a section on line 00 a; of Fig. 2.

Like letters refer to like parts in all the figures.

A represents any suitable base, upon which the field-magnets B andarmature G of an electric motor are mounted and are operativelyconnected and D are standards provided with bearings for the shaft 0 ofthe armature. This shaft C is extended and provided wlth a belt-pulley Cand a centrifugal or other governor 0 having connection with anoscillating lever E, which connection may be of any suitableconstruction permitting-the rotation of the governor upon the shaft andthe reciprocation of one of its collars C along the same as the balls ofthe governor approach or recede, in accordance with the speed of therotation of the shaft. A connecting-rod F extends from the upper end ofthe oscillating leverE, and is pivotally connected with a rock-arm orpivotally con- 11 ected with a shunt-arm G. In this instance theshunt-arm comprises a hub G, mounted on the pivot G seated in a bridge Hof nonducting material, extending from one of the field magnets to theother and insulated therefrom.

From the hub G there extends an arm G to which, as shown, theconnecting-rod F is pivotally secured. Said rod, however, may be secureddirectly to the shunt-arm G at one or the other side of its pivot. StopsH',projecting upwardly from the bridge H and into the path of theshunt-arm, are employed to limit the movement of said arm. Each end ofthe shnnt-arm G terminates in contactplates 1, secured to the arm byscrews 1, or in any other suitable manner, one upon the upper and theother upon the lower surface of the arm. F

At each end of the bridge H is a block H upon which is arranged a seriesof conductive strips or plates J, insulated from each other andterminating at their inner ends on a curved line, conforming to the pathof the ends of the shunt-arm G, the terminal plates I of which embracethe upper and lower surfaces of the strips or plates J,with which saidshunt-arm plates 1 are in contact. Each of the plates J is electricallyconnected by wire or other means J with alayer, or a portion of a layer,or it may be a collection of layers, of the coils of the field-magnet.

The line 1, by which the current of electricty is conducted to themotor, is connected with the first of the series of plates J at that endof the bridge, while the line 2, by which the current is furtherconducted, is connected with the diagonally-opposite plates .l' at theopposite end of the bridge. This line '3 extends to one of the brushes Kof the motor, and from the other brush K the line 3 OX tends, bywhichthe current iscondncted from the motor.

The operation ol. my invention is as tollows: Taking the shunt-arm inthe position shown in Fig. 2, the full strength of the cur rent is beingsupplied to the motor. Now it the labor oi work of the motor is reduced,the full strength of current necessarily increases the rapidity of therotation of the armature of its shaft. This causes the ballsofthegovernor C" to recede from the shaft, and by means of themechanical connection of the governor E the latter is caused tooscillate toward the motor, and through the medium of i theconnecting-rod F to swing the shunt-arm G on its pivot in the directionindicated by the arrows in Fig. The current then, instead of passingthrough the diagonally-opposite plates J of the opposite series and theshunt-arm connecting the same, will pass through a pair or pairs of thediag(mallyop posite plates .1, which are electrically connected withless than all the layers of the field-magnet, and therefore the strengthof the 'licliIl-magnet willbe red need, and the speed of rotation willbe correspondiugly reduced. Theposition of the shunt-arm plates l uponthe bridge-plates J is therefore controlled continuously when the motoris in motion by the ac tion ot the mechanical governor, the strength ofthe field-magnets decreasing in proportion as said governor moves theshuntarm a greater or less distance in the direction indicated by thearrows in Fig. l, and the supply of electricity being increasedproportioilately as the meehaiiiical governor moves said arm in theopposite direction. 13y reason of the broad surface of thecontact-plates I. .i the burning or fusing of the same is renderedpractically impossible.

The outline of the free ends of the contactplates need. not necessarilybe curved, and in such case the shunt-arm may be mounted to move in aline other than curved along over the plates of each opposite series bysuitable connection with the governor.

.l'lav-ing described my invention and its operation, what I claim is 1.The cmnbination, with the field-magnet and armature oi. an electricmotor, ol, a series of contact-plates arranged on each pole of thefield-magnet and electrically conncettal with the layers of the coilsthereol', and an intermediate shunt-arm cleetricallycininecied with theopposite series of plates and meehanically connected with a governorarranged to receive motion from the shall ol. the armat ure,substantially as specilied.

2. The comlunation, with each pole of the field-magnet of an, electricmotor, of aseries of insulated contact-plates, each electricallyconnected with the coils of one side of the magnet, and an interposedshunt-arm having contact-plates adapted to bear upon opposite surfacesof said contact-plates, and means for moving the shi'int-arm )latesalong the series of eontaetplates, substantially as specified.

1:3. The combination with the field-magnet of an electric motor, of aninsulated l)l'lll'f'1,il series ot' insulated plates at each end ol thebridge terminatingin a curved line and electrically coi'u'iected withthe coils of the field magnet, a shunt-arm pivoted on the bridge andterminating in colduct-plates, and stops projectingfrom the bridge tolimit the move ment of the arm, substantially as specified.

l. The combination of the magnet l3, bridge ll, having the blocks 'llthe insulated proj ecting strips 1, el ectrieal ly eon n ected with thecoils of the lield-niagnel', and the shunt-arm G, mounted on the pivotit, seated on the bridge and having the co1il'aet-plales 7], arranged toembrace the platesil, substantially as spccilied.

5. The combinatimi, with the magnet Ii, ln-idge ll, and plates .'I,mounted on said bridge, of the Slilllil'ritl'lii G, pivoted on saidbridge and havii'ig the plates 1, pivot (1, and the stops ll, projectingfrom said bridge, substantially as specified.

(3. The combination of the insulated plates J, the shunt-arm (5i,pivoted between them. the rock. or crank arm (i attached thereto, rod 1,and lover E, connecting said arm ti with the governor substantially asspecitied.

In testimony whereof I allix my signature in presence of two witnesses.

\V itnessos:

'W. 'DUvanL, Ii. S'U'JTl-IERLAN'D.

